Dish washing machine and liquid level measurement device and method thereof

Abstract

The invention discloses a dish washing machine and a liquid level measurement device and method thereof. The liquid level measurement device comprises an electrode module, a shielding module, a capacitive to digital conversion module and a processing module. The electrode module is mounted outside a container and comprises a liquid level pair and a reference liquid sensing electrode pair, the liquid level sensing electrode pair comprises a liquid level sensing electrode and a first grounding electrode, and the reference liquid sensing electrode pair comprises a reference liquid sensing electrode and a second grounding electrode; the shielding module comprises a first shielding electrode and a second shielding electrode, the capacitive to digital conversion module conducts differential potential driving on the liquid level sensing electrode and the first shielding electrode and the reference liquid sensing electrode and the second shielding electrode respectively, and a liquid level sensing capacitance and a liquid level measurement unit capacitance are obtained; the processing module calculates the liquid level height according to the liquid level sensing capacitance and the liquid level measurement unit capacitance. According to the dish washing machine and the liquid level measurement device and method, a non-contact mode is adopted to avoid pollution, the shielding electrodes are added so that anti-phase compensation measurement can be conducted, and external disturbance is avoided.

Description

technical field [0001] The invention belongs to the technical field of electric appliance manufacturing, and in particular relates to a liquid level detection device for a dishwasher, a dishwasher with the liquid level detection device and a liquid level detection method for the dishwasher. Background technique [0002] At present, there are many methods for measuring the height of the liquid level, for example, the capacitive water level monitoring method, which puts two parallel electrodes in the water, and one of the electrodes has an insulating layer on the surface, thus forming a gap between the two electrodes. Capacitance C, whose capacity is proportional to the depth of the electrode submerged in water. However, there are some problems with this detection method. For example, if it is used for a long time, scale will easily form and the detection accuracy will decrease; contact measurement must be fixed in the measured liquid, which will easily pollute the water sourc...

AI Technical Summary

Problems solved by technology

However, there are some problems with this detection method. For example, if it is used for a long time, scale will easily form and the detection accuracy will decrease; contact measurement must be fixed in the measured liquid, which will easily pollute the water source; traditional capacitive sensing technology is limited to its own Stability and external interference (such as human hands) often cause capacitance drift. Therefore, the ability to resist external interference is poor, EMI detection is often difficult to pass, and the requirements of CS (conducted immunity test) cannot be met.

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